Question
What factors contribute to the upper airway collapse in OSA patients?
Answer
The collapse of the upper airway in patients with Obstructive Sleep Apnea (OSA) can be attributed to a combination of anatomical and non-anatomical factors. Anatomically, individuals with OSA often have a narrow or crowded upper airway, which may be due to congenital conditions, genetic factors, or an increased volume of soft tissues in the upper air digestive tract. Conditions such as Treacher-Collins syndrome, which includes craniofacial anomalies, can lead to a crowded upper airway, and increased volumes in structures like the genioglossus, pharyngeal walls, and soft palate further reduce airway diameter. While OSA is frequently associated with obesity, about 60% of obese individuals do not have OSA, and lean individuals can also present with the disorder.
Non-anatomical factors involve the cyclical pattern of airway collapse seen in OSA. During sleep, airway collapse leads to hypopnea or apnea events, resulting in increased carbon dioxide and decreased oxygen levels in the blood. This excites sensory receptors that trigger an arousal from deep sleep, opening the airway and altering breathing patterns. Individuals may hyperventilate to rebalance blood gas volumes, but this often leads to further airway collapse upon returning to sleep. This cycle of collapse and arousal can occur over 300 times in a single night, severely disrupting sleep quality.
This Ask the Expert is an edited excerpt from the course, Obstructive Sleep Apnea: The Impact on Swallowing in Adults, presented by Kendrea L. (Focht) Garand, PhD CScD, CCC-SLP, BCS-S, CBIS, CCRE.
